Valve operating mechanism



' P" 1946. A. CHILTON VALVE OPERATING MECHANISM 3 Sheets-Sheet 1 FiledOct- 6, 1942 INVENTOR. Allan Chi/ton.

ATTEIRNEY April 9, 1946. A; CHILTON VALVH OPERATING MECHANISM Filed Oct.6, 1942' 3 Sheets-Sheet 2 INVENTQR. Allan Chi/for; .8! F 5 ATTORNEYApril 9, 1946. A. CHILTON VALVE OPERATING MECHANISM Filed Oct. 6, 1942 3Sheets-Sheet 3 INVENTOR. Allan Chi/fen ATTORNEY Patented 9, 1946 i iUNITED STATES'PATENT OFFICE VALVE OPERATING MECHANISM Allan Chilton.Ridgewood, N. 1., assignor to Wright Aeronautical Corporation, acorporation of New York Application October 6, 1942, Serial No. 461,029

11 Claims. '(Cl. 123-90) This invention relates to valve gears forradial Figs. 6 to 8 are top, end, and bottom plan views type aircraftengines. One of the objects of this respectively of the rocker armsaddle bracket; invention is to provide a valve gear which occu- Fig. 9is a section on the line 8-9 of Fig.7; pies less length axially oi thecylinders than the Fig. 10 is a section on the line lO-lil of Fig. 3;

arrangements heretofore used. Consequently, it and is an object of thisinvention to provide a valve Fig. 11 is a section through the push-pullconoperating mechanism for radial cylinder engines nection betwee therocker arm and valve stem. by which the overall diameter of the enginemay The drawings illustrate the application of the be reduced. To thisend the valve springs are inventionto an air-cooled radial engine. InFigs. disposed'at right angles to the valve stems instead 1 and 2, l0represents the engine crankcase with of concentric with the valve stems,as is the usual the usual axially offset intake and exhaust valvepractice. operating cams l2 and I2 01 which the intake In theconventional practice the rocker box is valve operating cam is indicatedat H. Finned cast integral with the cylinder head and the rock cylindersM are radially mounted about the er arm is journaled about a bolt whichextends 15 crankcase with integral intake and exhaust rockacross therocker box and is supported in bosses er boxes l6 and 5' respectively,having covers" on the sides of the rocker boxm As a result of and 11'.Intake and exhaust valve operating this construction. the valveoperating loads are push rods I8 and I8 are enclosed by the usualconcentrated in a small area on the sides of the tubular casings and 20'and are mounted parrocker box by the rocker arm supporting bolt 20 all'lto the axes of their respective valves. These thereby tending to crackthe rocker box. Therepush rods extend into housings 22 mounted aboutfore, it is a further object of this invention to openings 24 in thecrankcase adjacent the peprovide an improved supporting means for theriphery of the valve operating cams I2 and i2. valve gear rocker arm.According to this inven- The valve tappets comprise bell crank levers 26tion, a rocker arm saddle bracket is attached to 25 and 26' which areoppositely disposed in the the cylinder head within the rocker box andthis crankcase and are provided with cam followers bracket supports therocker arm bolt. This 29 and 29 mounted on one of their arms forenbracket may be forged so that a stronger congagement by the enginedriven cams l2 and i2 struction is possible with the result that thereis while the other arm of the bell crank levers exless tendency forcracking to occur about the sup- 30 tends radially out through thecrankcase openport for the rocker arm bolt. lugs 24 for operativeengagement with the push Furthermore, in the usual radial engineconrods18 and i8 respectively. The crankcase ill struction, the intake and.exhaust valves are is of such diameter at this point, and the housingsmounted on opposite sides of each cylinder and 22 are so disposedrelative to the valves of the these valves are inclinedtothe cylinderaxis while associated push rods, that these rods are subthe valveoperating push rods are substantially stantially parallel to the axes oftheir associated radial. With such a construction, there is arelavalves. As is the usual practice in radial aircraft tively largeangle between the valve axis and the engines, the intake and exhaustvalves of each axis of its associated push rod thereby producingcylinder are circumierentially spaced on oppoa side thrust on the rockerarm. This side thrust 40 site sides of ,the cylinder with their axesinwardly also tends to cause rocker box failures. Thereinclined withrespect to the cylinder axis, as best fore, it is a further object ofthis invention to seen in Fig. 1. Therefore, the axes of an intakeprovide a valve gear construction in which the and an exhaust valve ofspaced cylinders will be valve and push rod axes are substantiallyparallel. substantially oppositely directed. Consequently, Other objectsand advantages will be obvious it is possibletomount the oppositelydisposed bell from or will be pointed out in the following decranklevers 26 and 26' about a common shaft scription with reference to thedrawings, in which: 28 for engagement with the oppositely directed Fig.1 is a front elevation of a portion of a push rods I8 and i8 extendingsubstantially radial aircraft engine withasection of the crankparallelto the axes of the intake and exhaust case broken away; valvesrespectively of such oppositely directed cyl- Fig. 2 is an enlargeddetail of a. portion of inders. Asbest seen in Fig. 1 and at 30 in Fig.4,

Fig. 1; these intake and exhaust push rods are-axially Fig. 3 is a topplan view of the rocker box with oiiset corresponding to the axialoffset of the inthe cover removed, as viewed along the line 3--3 takeand exhaust valve operating cams l2 and of Fig. 4; I2. Rocker arms 32are interposed between each Fig. 4 is a section on the line 44 of Fig.3; valve push rod and the associated valve 33. These Fig. 5 is a sectionon the line 55 of Fig. 4; rocker arms are provided with a sphericalbearlevers 26 and 28' to operate push rods l8 and i8 respectively.Rocker arms 32 operatively interconnect each push rod with its valve andeach push rod is disposed substantially parallel to the axis of itsassociated valve so that each push rod, rocker arm and valve axis arecoplanar. As a result of this construction, no side thrust istransmitted to the rocker arms thereby tending to reduce rocker boxfailures.

The rocker box construction of the intake and exhaust valves is similarso that the description of one will suffice. The rocker arm 82 isjournaled on bushing-88 about a fulcrum bolt 38. This bolt is receivedwithin bores 40 in the rocker arm saddle bracket 42. This bracketconsists of a U-shaped or saddle-like structure having downwardlyextending side portions 48 and a bridge 44 with a reinforcing rib 46.The downwardly extending side portions 48 are provided with bores 40 forreceiving the rocker bolt 38. Guide extensions 50 are provided at thebottom of each side portion 48 for reception in correspondingly shapedrecesses in the rocker box. The rocker arm bolt 38 is supported in bores40 in the sides 48 of saddle bracket 42 and has-end flanges 56 whichengage the flat upper surface of the rocker box IE to prevent turning ofthis bolt.- The side portions 48 of the bracket are snugly receivedbetween the sides of the rocker box housing," as best seen in Fig, 10,and bosses 52 are provided on this bracket for securing same to thecylinder head within the rocker box by bolts 54. The saddle bracket 42thereby transmits the valve operating forces directly to the cylinderhead and since this bracket may be forged, a much stronger rocker boltsupport is possible as compared to the usual support for this bolt onthe sides of the cast rocker box. This-construction thereby furtherreduces rocker box failures. Also, this method of supporting the rockerarm permits a much simpler machining of the rocker box.

In the usual valve gear construction, the valve spring is disposedconcentric with the valve stem so that the valve spring adds to theengine diameter. By placing the valve spring at right angles to thevalve stem axis, as illustrated in Figs. 4, 5, and 10, it is possible toreduce the engine diameter. An arm 80 is integrally formed with therocker arm' 32 and extends inwardly therefrom. Two sets of helical valvesprings 62 are mounted about guide rods 64 on opposite sides of the pushrod 18. One end of these spring sets bears against the front of therocker box while the other and bears against washers 66 carried by atransverse plate 68. This plate has bearing seat for engagement by thespherical end 10 of the depending arm 60 of the rocker arm. A push-pullconnection is provided between the rocker arm and the valve stem. Anysuitable connection may be used." However, the connection disclosed inthe previously cited co-pending application of R. Chilton is preferredand is illustrated in Figs. 4 and 11. The upper end of the valve stem 12is grooved at 14 to provide a head portion 16. The rocker arm isprovided with a boss 18 having a cross bore ll. A trunnion l2- issupported in the cross bore and has a T-shaped slot 84 for the receptionof the head portion 18 of the valve stem 12, as best seen in Fig. 11.The lower end of the boss 18 is bifurcated as at 84 and reeved at 88 toallow for the passageof the valve stem head ortion 18. As a resultofthis construction, the push rod I8 is operable to open the valve 33against the bias of springs 82. These springs being disposed at rightangles to the valve axis, produce a corresponding reduction in theengine diameter. Also, in view of cal disposition of the valve springs82, these springs, like the push rods, do not transmit any side thrustto the rocker arms.

From the above description of the invention it will be seen that thevalve gear has been designed to reduce rocker box failures on radialtypeengines and at the same time reduce the overall diameter of the engine.

While I have described my invention in detail in its present preferredembodiment, it will be obvious to those skilled in the art, afterunderstanding my invention, that various changes and modifications maybe made therein without departing from the spirit or scope thereof. Iaim in the appended claims to cover all such modifications and changes,

I claim as my invention:

1. In an engine having a plurality of radially disposed cylinders withthe intake and exhaust valves of each cylinder circumferentially spacedon opposite sides of the associated cylinder, and with the axis of eachvalve inclined inwardly and downwardly with respect to the associatedcylinder whereby an intake valve of one cylinder and an exhaust valve ofanother cylinder have substantially alined axes; valve gear means forsaid valves comprising axially offset intake and exhaust engine drivencam means, a push rod for each valve disposed substantially parallel tothe axis of the associated valve, the push rods for intake and exhaustvalves respectively being axially offset to correspond to said camoffset, and valve tappets each comprising a rocker member having one armadapted to be actuated by said cam means and having the other armextending radially outward for operative engagement with a valve pushrod, the rocker members operatively connected with an intake valve pushrod of one cylinder and a substantially parallel exhaust valve push rodof another cylinder, respectively, being pivotally mounted about thesame axis, oppositely disposed and axially offset to correspond to saidcam offset.

2. In an engine, a plurality of radially disposed cylinders each havingintake and exhaust valves, valve gear means for said valves comprisingaxially offset, engine driven intake and exhaust valve cam means withinthe engine crankcase, a push rod for each valve extending inwardlytoward said crankcase and being disposed substantially parallel to thatportion of the general crankcase surface adjacent the crankcase end ofsaid push rod, the push rods for the intake valves being axially offsetfrom the exhaust valve push rods to correspond to said cam offset, andvalve tappets each comprising a rocker member having one arm adapted tobe actuated by said cam means and a second arm extending radiallyoutward through said crankcase into operative engagement with a pushrod, said rocker members being mounted in pairs about the same axis,oppositely disposed and axially offset to correspond the symmetrito saidcam ofiset, one rocker member of each pair being interposed between theintake valve cam means and a push rod for an intake valve of aparticular cylinder, while the other rocker member of each pair isinterposed between the exhaust valve cam means and valve of anothercylinder.

3. In a valve gear for an engine cylinder, a rocker box comprising sideand bottom walls integral with the head of said cylinder, a U-shapedbracket extending across said rocker box and secured thereto, saidU-shaped bracket having its open end facing the bottom of said rockerbox with its sides fitted between the sides of said box, a rocker armbolt supported by and extending between the sides of said bracket, avalve operating push rod, a rocker member journalled about said boltbetween the sides of said bracket and having opposed arms in operativeengagement with said rod and valve respectively, said rocker memberhaving a third arm extending toward the bottom of said rocker box, andvalve spring means acting against said third arm.

4. In a valve gear, a rocker arm box having side and bottom walls, aU-shaped bracket extending across said rocker box and secured thereto,said U-shaped bracket having its open end facing the bottom of saidrocker box with its sides fitted between the sides of said box, a valveoperating rocker arm, and means for pivotally securing said rocker armbetween the sides of said bracket.

5. In a valve gear for an engine cylinder, a rocker box comprising sideand bottom walls integral with the head of said cylinder, a U-shapedbracket extending across said rocker box and secured thereto, saidU-shaped bracket having its open end facing the bottom wall of saidrocker box with its sides fitted between the sides of said box, a valveoperating rocker arm, and means for pivotally securing said rocker armto said bracket.

6. In a valve gear for an engine cylinder, a rocker box comprising sideand bottom walls integral with the head of said cylinder, a U-shapedbracket extending across said rocker box and secured thereto, saidU-shaped bracket having its open end facing the bottom of said rockerbox with its sides fitted between and engaging the sides or said box, arocker arm bolt supported by and extending between the sides of saidbracket and a valve operating rocker arm journalled about said bolt.

7. In combination, an engine having a crankcase, a plurality of radiallydisposed cylinders mounted about said crankcase, an intake valve and anexhaust valve for each cylinder, said valves being circumferentiallyspaced relative to the engine of their associated cylinder, and a valvegear for each or said valves comprisinga valve operating push rod, thepush rods for the intake and exhaust valves of a cylinder extendinginwardly to the engine crankcase and being so orientated that they crosseach other inboard of the outer cylindeiend and said push rods eachbeing disposed substantially parallel to that portion of the generalcrankcase surface adiacent to the crankcase end of the associated pushrod.

8. In combination, an engine having a crankcase, a plurality of radiallydisposed cylinders a push rod for an exhaust axis and being disposed onopposite sides mounted about said crankcase, an intake and an exhaustvalve for each cylinder, said valves being circumferentially spacedrelative to the engine axis and being disposed on opposite sides oftheir associated cylinder, and a valve gear for each of Q said valvescomprising a push rod and a rocker arm having its opposed ends inoperative engagement with'the associated valve and push rodrespectively, each push rod and associated rocker arm being disposed ina common plane with the axis of their associated valve, and each pushrod extending inwardly to the engine crankcase and being disposedsubstantially parallel to that portion of the general crankcase surfaceadjacent to the crankcase end of the associated push rod.

9. In combination, an engine having a crankcase, a plurality of radiallydisposed cylinders mounted about said crankcase, an intake and anexhaust valve for each cylinder, said valves being circumferentiallyspaced relative to the engine axis and being disposed on opposite sidesof their associated cylinder, a valve gear for said valves comprisingvalve operating push rods, each push rod extending inwardly to theengine crankcase and being disposed substantially parallel to thatportion of the general crankcase surface adjacent the crankcase end ofthe associated push rod, engine driven cam means, and valve tappets eachcomprising a rocker member having one arm adapted to be actuated by saidcam means and having another arm extending substantially radiallyoutwardly for engagement with one of said push rods.

10. In combination, an engine having a crankcase, a plurality ofradially disposed cylinders mounted about said crankcase, an intakevalve and an exhaust valve for each cylinder, said valves beingcircumferentially spaced relative to the engine axis and being disposedon opposite sides of their associated cylinder, valve gear means forsaid valves comprising a push rod extending inwardly toward said pushrods being so dispomd that push rod oi one cylinder is substantiallyparallel with the exhaust valve push 11. In combination, case, aplurality. of

therefrom.

' CHILTON.

